How can I count how many numbers are different from '-1'?

Hi,

Example: Suppose we a have a matrix A

A= [1 -1 0 -1 0 0 -1 0 -1 -1 -1 -1 -1 -1 -1]

How can I count how many numbers are different from '-1'?

[Shubhashree Bal]

Search for how many negative number exists in A. than subtract that from length of array. Or Write a loop for how many positive number exists in array.

Code attached below:

Close all;

clear all;

A= [1 -1 0 -1 0 0 -1 0 -1 -1 -1 -1 -1 -1 -1];

count = 0;

for i = 1: length(A)

if(A(i)>=0)

count = count +1;

end

end

[Davide Conti]

Ok thanks, but if i wanted to do it for every line of my matrix?

For examples:

1 -1 0 -1 0 0 -1 0 -1

4 2 3 -1 0 3 1 2 -1

in this case for the first row the numbers different form '-1' are 5, in the second row they are 7.

With your loop it comes out that in the second row they are 12, because it considers the first row.

Answer 1

[Fangjun Jiang]

start with B=A~=-1

[Walter Roberson]

And then sum() along the appropriate axis.

Answer 2

[Pedro Martinez]

Total = sum (A==-1);

[Walter Roberson]

That gives the number of rows of -1 but the user wants the number of columns that are not -1